1. Technical Field
This invention relates in general to magnetic recording devices and in particular to an air bearing surface on a magnetic read/write head that flies above magnetically recorded media at a relatively constant height.
2. Background Art
To successfully achieve file performance, a magnetic read/write head must fly steadily at a given fly height over the disk with minimal variations. Since the variations in fly height are dependent on the various sensitivities of the fly height to the process parameters as well as the variability of the parameters, a state-of-the-art air bearing surface (ABS) design technology and tight process control are mandatory to minimize such variations. Common dominant process parameters affecting fly height include gram load, pivot location, crown and etch depths.
Negative pressure bobsled slider (NPBS) air bearing designs are widely popular. These designs utilize relatively simple multi-step front and rear pads for design easiness, but show a fast take-off, small fly height variability, and good altitude loss. Conventional drives operate in contact stop-start (CSS) mode, where the heads are in contact with the disk as the drive is turned off. Since the contact between heads and disks is a major source of mechanical integration problems, a load/unload mechanism has been developed. The mechanism, which would lift the heads from the surface of the disks as the actuator travels beyond the outer diameter of the disk would completely prevent head-disk surface contact by parking the heads outside of the disk stack.
NPBS design for CSS mode requires a fast take-off performance to minimize any potential problem related to wear and contamination between heads and disks. This requirement needs enough rear pad area to build up the pressure at low speed. For higher operating speeds, rear pad size and geometry are directly related to the fly height sensitivity to crown and bigger pad size normally increases the fly height variation. However, take-off performance is not an issue for drives that employ load/unload mechanisms. Thus, the rear pad can be designed without regard to size limitations to improve ABS performance.